Light projector



June 16, 1931. l c. A. a'HALvoRsoN. JR 1,810,604

` LIGHT PROJECTOR Fi1ed`Feb. 28, 1924 s sheets-sheet i .w 9.7/16 Www- He June 16, 1931. c. A. B. HALvoRsON. JR 1,810,604

LIGHT PROJECTOR Filed Feb. 28, 1924 3 Sheets-$heet 2 Figa' -ngz June 16, 1931- c. A. B. HALvoRsoN. JR 1,810,604-

' LIGHT PROJECTOR Filed Fe'b. 28, 1924 3 sheets-sheet s fn Venof:

T0/Wwe# .76? 6i jVa/vorson JA;

Patented June 16; 1931 CROMWELL A513. HALvon'soN, Jn,

or LYNN, MASSACHUSETTS, AssreNon 'ro GENERAL' ELECTRIC CoMPANY,` lA 'CORPORATION or NEW Yonx Lienz: PROJECTOR Heretofore light projectors have been made having mirrors of various sorts, sometimes of glass and sometimes of metal. AIn the case where metal mirrors are used, various. expedients have been devised to minimize 'or prevent the corrosion ofthe reiecting surface and to prevent any obstructing matter, such as dirt, from comingv into contact with the reiiecting surface. For instance, a lacquer has been sonietimes used to protect the surface, but it has been found that it becomes -overheated and deteriorates when used 1n connection with a high intensity type of arc. Furthermore, as it ages, it'absorbs a larger percentage of the light, thereby impairing the eiiiciency of the instrument. The objections mentioned in the foregoing become parlticularly marked`when theV source of light in a projector has to be occulted while the light is oli as in the case where the projector is used as a signalling device. n

In order to overcome these objections, I have provided a metal mirror which is covered by a glass velementin such a manner that the mirror is sealed. In this connection,

Ihave found that a curved hood is preferable to a flat one inasmuchas the curved form is less liable-to crack. In the case of a 'projectorfin' whichthe source of light-isa high powered electric lamp of the bulb typeenclosed ina housing and in which the source of light `must beocculted between signals and I iin particular when the signalling device is I piece for sveallingthe reflector, ymuchbetter reto be used subject toweather conditions or subject to spray from sea water, it is very important to have'the mirror and the housing V'effectively sealed. I have found that all though one individual glass piece .may be.

'used for the housingand a separate glass sults are obtained where a unit piece of glass l Aisgused for both. A much more eflicient'con-- struction results in the latter case inasmuch -1 asfthev light does not have to pass through the glass twice. In order to accomplish the foregoing I pfrovide a single sealed 'hood com'- mon to the housing and to the reflector.

It is an .object of my invention lalso 'to provide other rdetails of improvement tend- Applicauon filed February 2s, i924. seriai' No. 695,868.

l ing to increase the efiiciency and serviceability of a projector of the above character.

The means for accomplishing the results of my invention are hereinafter more fully set forth and claimed.-

In connection with the specification, I wish toy make reference to the accompanying drawings in which Fig. 1 isa side elevation of the signalling lamp and its pedestal; Fig. 2 is a front elevation ofthe lamp without the pedestal; Fig. 3 is Fig. l; Fig.4 is a lector clamping signed to show. the flexible contact of the clamp to allow for expansion of the glass as a result of the heat of the lamp; Fig. 5 is a rear elevation with the reiiector broken away showing the clamps for holding the reflector frame in p Ishutter used for signalling is shown through an opening in the casing. `vThisfiguregalso shows the weather strips. The lamp casing isbroken away to operating mechanism. In the lower part, this figure shows the balancing'weight which is used to ,maintain the lamp casing in balanced condition; Fig. 6 is a cross section through the lamp casing and through the reflector showing the water protecting globe; Fig. 7 is a cross section through the shutter operating mechanism; Fig. 8 is a plan View of the shutter.operatingmechanism; showing how the shutter is controlled lin one direction by hand, or electrically,l and in the vopposite directionby aspring. This ii .the rack through which Vmovement is communicated to the shutter by rmeans of the seg- Fig. 11 shows a Referring .y in Fig.y 1 theprojector isjshown mounted on an arm 3 pivotally mounted on the base 2 and may be rotated about a'v'ertical axis, that is, an axis perpendicular to the base. On the upper enelv ofthe arm 3there is a horizontally projects to the left beyond the collar 5.,. To the projectsA disposed shaft 4, one end of which gare also showsA a cross sectionof the .casing showing,l the shutter operating mchanism in modilication; and form of the shutter-operating mechanism.

more in detail to the drawings,

position. In Vthis figure the show partof the shutter i a clamp having'a lever 7 The terminals 8 and 9 of the arm 6 are adapted to serve as bearings for receiving the housing 10 in which the incandescent lamp 11 is located (see Fig. 6). The housing 10 is provided with suitable bearing stubs 12 on the ends of the curved member 13 located on the upper part of the housing, and forming a part of sa1d housing.

It will be observed that these bearings l2 are above the central portion of the housing. About these bearings 12 as a'horizontal axis, the housing may be rotated. In order to properly balance thehousingg there is secured to the under part of the housing a balancing weight 14. The'front part of the housing is provided with an elliptical opening 15 (see Fig. 5) through whichthe signalling shutters 16 and 17 can be seen. As shown in Fig. 7, these shutters project down from a suitable bearing. For example, the shutter 17 termi` nates in a hollow bearing 18 which rotates about the pin 19. This pin is secured to a projecting member 20 secured to the housing. The lower portion ofthe pin is provided with a collar 21 which serves to hold the hollow bearing 18 in place. As an integral part of the bearing 18, there is a segmental gear 24 through the medium of which the shutter 17 is operated, as will presently appear. The

` bearing 18 serves in turn as a support for the bearing 23 of the shutter 16 with which the shutter is integral. Furthermore, a segmen tal gear 22 is also integral with the bearing 23 which gear 22 serves for operating theshutter 16. As shown in Fig. 8, the gears 22 and 24 are olfset and work within the rack frame 25. The rack 25 is provided with a shaft, 26. This shaft is held in a suitable bearing construction ,in the framework, which construction comprises the elements 27 and 28. It will be seen that within this bearing there is provided a spring 29, which spring normally tends to retain the rack against the element 27 in view of the fact that the shaft 26 is provided with a collar 30, which collar is rigidly secured to the shaft 26. With this construction, it will be seen that by moving the rack 25 back and forth, the gear segments 22 and 24 on the oscillating pin 19 and consequently the shutters 16 and 17 will be 0perated with the result that signals may be transmitted by interrupting the light between the lamp 11 and the reflector 31 (see Fig. 10) In Fig. 10 the shutters are shown open and therefore the light from the lamp 11 is shown passing through `to the reflector and extending to the left in the shape of a beam on either Aside of the housing 10.

Referring to Fig. 5, it should be noted that around the opening 15 there is provided an oval shaped packing 32 which, as presently will appear, serves to prevent water from trickling -into the housing between the glass lips and the housing there is interposed the packing 32.

The reflector 31 is provided preferably with a silver reflecting surface which may be backed and reinforced in anysutable manner as for example with copper and with any other addit1onal reinforcing material behind that. As shown in the drawings, the reflector is protected in the rear preferably 34 and the reflector proper there is provided a cushion 35 of any suitable resilient material. The rellector 31 and the glass 33 are held together as a unit by the casing 34, the

rim of which is spun over the edge, as in- `dicated. This rim is reinforced and made tight by annular retaining rings 36 and 37, Figs. 6 and 10. Furthermore, the glass shield 33 is suitably .sealed where it comes in contact with the reflector to preserve the enclosure air tight. If desired, the enclosure ma be held under reduced pressure, that is, 1n a state of partial vacuum. It will'thus be seen that the reflector surface with its protective glass and metallic auxiliaries forms a unit, which unit is held in position within the ring 38 by clamps 41 held by studs 39 and nuts 40 disposed around the rim of the unit and secured to the housing. Furthermore, between the clamps 41 and the nuts 40, I provide cushion springs 42 in order to permit the unit to expand and contract under the influence of the heat generated or produced by the source of light or otherwise.

Referring to the shutter construction and the method of operating the shutters for the purpose of signalling, it will be observed that the shaft 26, Fig. 8, is engaged by a Ufshaped member 43, the ends of which are -secured to the lower extremities of the bifurcated arm 44, Fig. 6, which arm 44 is pivoted at the point 45. It will be observed that the arm 44 has connected to it midway between the shaft 26 and the pivot 45, a rod 46 which terminates in a handle 47. By pulling the handle, the shaft 26 is forced to the right with the result that the shutters 16 and 17 are drawn open to a position indicated in Fig. 10. Upon releasing the handle 47, the spring 29 restores the rack to its normal position, Fig. 8,.'"thereby closing the shutters 16 and 17. The closed position of these shutters is indicated in Fig. 9.

by a `metallic casing 34.` Between the casing v as indicated in Fig. 11, with the pivoted armV The control of the racl, 26 may be varied,

magnet suchas the electromagnet 48, the latter being under the control'of a suitable key .49 and in series with a suitable battery 50. `With the arrangement shown in 11 it is obvious that theshutters may be operated with equal facility either by handle 47 or bythe electromagnet 48. i

It will thus be seenthat I have devised' a simple, inexpensive and rugged mechanism which may be used for signalling purposes, and which may not be detected, being completely occulted, except during the time the signals are being actually transmitted. It should bepointed out that provision is made for Ventilating the housing. This is done by 'providing in the upper part of the housing,

Fig. 6, just below the cap 51, a series of openings 52 through which the hot airmaybe passed out. Suitable openings are also provided in thelower part of the/'housing below the lamp 11 to admit the cool air and to enable the draft to circulate.- With the construction shown and described, referring in particular to Fig. 1, it will be seen that the signalling device may be rotated as a whole abouty an axis perpendicular to the base 2 and at the same time may be lrotated about the horizontal axis through the bearings 12. In this connection, I will point out that I provide suitable clamps 53 for clamping the housing in any tilted position about the horizontal axis.

I wish it understood that although I have shown my invention in connection with a speciic type of construction, I do not Wish to be so limited inasmuch as in view of 'the disclosure, modifications will readily suggest themselves to those versed in this art without departing from the scope of the claims appended hereto. i

What I claim as new and desire to secure A by Letters Patent of the United States, is:

v 1. In a projector, a metallic reflecting surface 1n the form of a surface of revolution, sa1d surface extending in one direction, a

transparent h ood covering said reflecting suring a focal pointlying outside of said hood,

a source vof light at the focal point of said reflector, a second section of said hood also in the form of a surface of revolution about an axis non-coincident with said iirst axis, said elements being located in cooperative relation. f

v2. In a projector, a metallic reflecting surface inthe form of a surface of revolution, said surface extending in one direction, a transparent hood closing said reflector, means for sealing the reflector and .the hood together to form a sealed closure for the reflecting surface, said hood having a section of its surface also in the form of a surface of revolution extending in the opposite direction an 'axis common to that of the reflectingsurface, said reflecting surface having a focal point lying outside of said hood, and a source of light -at the focal point of said reflector,

a second section of said hood also in the form of a surface o f revolution about an axis noncoincident with said axis, said elements being located in cooperative relation.

3. In combination, a reflector having a focalizing reflecting surface and a hood connected to the reflector by a tight joint and entirely enclosing such surface, said hood having transparent sides tapering toward the axis of the reflector and terminating short ofthe focal region of the reflector and being provided with a concave wall of transparent material curving about the focal point of the reflector.

4. In combination, a reflector having a focalizing reflecting surface and a hood connected to the reflector by a tight joint and entirely enclosing such surface, said hood having transparent sides tapering toward the axis of the reflector and terminating short of the focal region of the reflector and being provided with a concave wall curving about an axis extending through the focal point of the reflector and extending transverse the axis of the reflector.

5. In a projector, a housing having a window, a light source in .said housing in front of the window, a reflector located outside said housing with its reflecting surface facing said window, a transparent hood located between the reflector andthe housing and entirely enclosing the reflecting surface, said hood having a portion which covers said window, and means connecting the hood to the rim of the reflector and to the housing, said reflector and hood projecting beyond the casing to define an .area for the passage of light from the reflecting surface.

6. In a projector, a housing having a window, a light source in said housing in front of the window, a light interrupter for the light source, means for operating the interrupter, a reflector located outside said housing with its reflecting, surface facing said window, a transparent hood located between the reflector and the housing and entirely enclosing the .reflecting surface, said hood having a portion which covers said window, and means connecting the hood to the rim of define an area for the the reiiector and to the housing, said reiiector I and hood projecting beyond the casing to deine an area for the passage of light from the reflecting surface. l j

7 In a projector, the combination of a reflector having a reiiecting surface, a transparent hood in front of the reiecting surface which is connected to the rim of the reiectory to form a' tight joint and to entirely enclose' the reflecting surface, a housing oflsmaller size than the reflector connected to the hood, said housing having an opening facing toward the refiector, andmeans for supporting a light source in said housing.

8. In a projector, the combination ofa reliector having a reflecting surface, a transparent hood in front of the refiecting surface which is connected to the rim of the reflector to form a` tight joint and to entirely enclose the reflecting surface, said hood havingv a centrally inwardly curved portion, a housing attached to the hood, said housing having an opening facing said inwardly curved portion,

and means forsupporting a light source in said housing, said hood and reflector pro,- jecting beyond the confines of the housing to 'said reflectingsurface.

9. In a projector, the combination of a reflector having a reflecting surface, a transparent hood in front of the reflecting surface Which-is connected to the rim of the reflector to form a tight joint and to entirely enclose the reiecting surface, a housing of smaller size than the reiector connected to the hood, saidhousing having an opening facingrtoward the reflector, means forsupporting a light source in said housing, and a d -movable shutter means in the housing for covering said opening.

In Witness whereof,K I have -hereunto set s y my hand this 26th day of February, '1924.

'CROMWELLA. B. HALVORSON, R. Y

passage of light from 

